The problem has to of course be with the hub, either locknuts not tightened or damage to cups/cones. As you've overhauled the hub it can't be my first guess - a broken able. You need to make sure the locknuts are properly tightened against the cones, and if so take the hub apart again and inspect the surfaces. Also, do not rise the balls.
Last edited by cny-bikeman; 04-04-14 at 04:36 AM.